It depends on how you are going to run your fans. Obviously using it as a carbon scrubber inside the tent (using it to recirculate air inside) will decrease smell a lot more, but it takes up a ton of room and doesn't do anything for cooling. Sticking it on the exhaust end of your cooling ducting should be just fine, no need to take up all that room inside. Unless your tent is like mine.... I have a solid 2-3 feet of empty air up top.
Okay cool thanks man I think that's what I'll do. Not growing in an apartment or anything so just reducing the smell a little should be good enough.
I exhaust through the filter outside of the tent. I use a 4'x2x'5' grow tent, 40 cubic feet. I have a 400 CFM, 6" inline fan for exhaust through a 6" carbon filter. I use a 600W HPS cooltube during summer, fall and winter open hood. The fan speed controller is turned as far down as it goes, and I usually still have temperatures on the low side, they are at like 73-75 degrees right now open hood. I used to run with the filter inside, but I noticed no real difference in efficiency in terms of cooling and odor control either way, so now I just have it outside for space. I believe it is a bit less efficient when you blow through the carbon filter, instead of suck through it, however I don't think it makes a difference whether it's inside or outside the tent. my setup is kind of like this: (fan) [ ](<- tent) v===[]===[=---=] [] [xxxx] ^ [xxxx] l (filter)
TDS meter is easy. Turn it on dry, then stick the end in the water and read the screen. Used to use those all the time repairing filtration systems.